I can only speak for myself, but I only remove the bottom old leaves that are past their best anyway, with the aim of improving the air circulation. Unnecessary high humidity caused by moisture trapped between the moist compost/soil and massive lower leaves can aid blight spores.
I never remove any of the top healthy leaves for the reasons you pointed out, other that side shoots and the tops when they reach the limit of how tall I'm prepared to let them grow.

As usual we've packed far too much into the polytunnel and I found one of the potted tomatoes that had been shoved to the back looking very poorly, black stems and leaves. It got hauled out immediately - I'm just hoping whatever the problem was won't affect anything else - although it all looks pretty healthy for now. I've swapped round a couple of tomatoes and an onion squash to try and alter the air flow a bit.

Maggie

Never doubt that you can change history. You already have. Marge Piercy

Air flow is a reason I hadn't heard before, and it seems to be the only one you guys take seriously. I'd never been entirely convinced about the sunlight theory, because I've observed shaded tomatoes ripening before those growing right next to the glass.

I've been out and picked a few leaves off the bottom - most of them looked fine, but it was very crowded in there. Still is, really but I'll try not to alarm my tomatoes too much with excessive leaf-pulling

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Rachel

Take nobody's word for it, especially not mine! If I offer you an ID of something based on a photo, please treat it as a guess, and a starting point for further investigations.

Commercial growers,always remove the lower leaves,and as everyone's suggested,this is counter the prob of blight.which thrives in stagnant air.I've grown Sweet Million this year,and they are very leafy,so I'm pulling them off big style.

I took 80% of the leaves off my toms because they got blight and I've never had such a fabulous harvest of fast ripening toms before! I reckon it's because the sun has been able to get at the fruit ripening it up more quickly. I'm going to do this every year from now on, blight or no blight! I should mention that all the toms (the fruit) were already large and finished growing, so they just needed ripening. But don't do this if you live in a very hot country because they might get scorch from the sun.

I just had to remove a lot of leaves from my tomatoes, due to me accidentally droughting them and the leaves at the bottom pretty much dying (It had been a very hot couple of days). They haven't done anything since really, but they seem to be getting healthier.